Graying of split-image when using 105mm Micro-Nikkor f/4.0 on FM2

I am using a 105mm Micro-Nikkor f/4.0 (AI) on my FM2 and find that at

some distances one half of the split-image on my focusing screen goes

dark gray to black. Although focusing is not impossible, it is more

difficult. This doesn't happen with any other Nikkor lenses on this

body. Could it be that I need a different focusing screen? Has

anyone else ever exprienced this problem? It is an f/4.0 Micro, not

a 2.8.

This is a common problem with f/4 lenses and standard split-image finders. The close focusing of the 105 micro makes the problem worse as the lens effectively gets slower as it's focused closer (this is actually true for all lenses, it's just more noticable on micros).

 

An E2 screen might be a good choice for you.

On many macro lenses the maximum aperture decreases when the lens is focused closer. The reduction in light will affect a split image focusing screen. You will also get the same effect when you are using the depth of field preiview function.

 

this is normal

I don't know if the FM2 will accept different focussing screens, but if they can, try out a Type R, or possibly, Type M screen.

 

Alex

Yes, the FM2 accepts replacement screens, and there is no R or M. They are the B2, the plain groundglass screen, and the E2, the "architectural" screen, which is a B2 with the grid made famous by the N80.

You can simulate the effect with any lens by using the depth-of-field preview button at f/4 or smaller. Try focusing with the fine groundglass ring surrounding the split-image center spot to help decide whether you want to use groundglass focusing all the time - that's what you will have with the other screens. Right now, the only thing you can't do is focus in the exact center of the image.

As others have said get a B2 or E2 screen. The 105/4.0 is said to be a better macro than the 105/2.8 AIS Micro-Nikkor and it has more free working distance than the AF 105/2.8D Micro. If you center your eye you should not have the problem with this lens near infinity. When you focus to 1:2 you are looking through an f/5.6 lens and if you add the PN-11 and go to 1:1 it�s become an f/8.0 so the phenomenon is unavoidable. This is not a defect, it�s physics. With an F2 or F3 you could get an "R" screen but most would prefer a "B" screen anyway.

 

Many newer macro lenses throw-a-way focal length with IF to focus closer and avoid this problem but you loose free working distance. Your 105/4.0 has better free working distance at 1:2 than the new AF 70~180/4.5~5.6 for example.

 

Don�t get antsy and dump the lens as it�s a fine lens. Just get a B2 or E2 screen.

 

Regards,

I *think* that the new FM3A B3 and E3 should work as well. You may have to run an exposure test to double check your meter calibration. Personally, I'd take a brighter viewfinder over the small hassle of adjusting the ISO dial.

 

Anyone ever see an H screen?

Note that the problem is worse if your eye is even a little off-center

behind the eyepiece. If the effective aperture is too slow, there's

no avoiding blacking out half the split image on the standard

type K screen, but before you give up completely, adjust the

position of your eye behind the eyepiece. At a marginal

aperture, you may find it usable if and only if

your eye is precisely centered.

Thanks to all for the many responses. I will look into alternate focusing screens as a solution. It struck me that I could have figured this out if I had just thought a little, so thanks to all also for reminding me to use my head. Cheers.